First of all I want to specify my final goal: use the Solidify Modifier in order to create a cage.
I think that my workflow, used since now,
Duplicate my low poly
Alt + S with the new mesh (i.e. cage)
isn't the way to achieve the best result, because it creates too much distorsion and doesn't preserve the original shape of my low poly, in particular with hard surfaces' meshes.
Therefore I found the solidify modifier that works pretty well. There's only one problem that i will show you with an easy example:
1) This is my High Poly
2) This is my Low Poly
I duplicate my Low poly and then with my new mesh (cage) I apply the Solidify Modifier in order to cover my high poly. The problem is that the solidify modifier double the mesh. In the final result i have my low poly, high poly and the cage, with 2 "meshes" (not divided, they are still a unique mesh in the Outliner) one inside the other like in the image below.
How can i delete the inner mesh?
In a simple mesh could be easy, like this cube, but when i have complex artifacts?